Inefficiency of search algorithms for intranet or corporate websites caused by poor design and/or implementation

I noticed recently that some of the search features on corporate websites and intranets seem to have implemented some of the search algorithms that are commonly associated with Facebook Graph Search or Google's SEO ranked search results.

This is commonly seen when a user enters a very specific keyword but the exact matching results are not returned or not ranked highly on the search results, whereas a partially matching result will be ranked highly.

My suspicion is that with many organizations creating social networks and doing extensive analytics on internal traffic have the tendency to implement the types of search algorithms that place more weight on criteria such as recency and number of existing page views when returning search results. Unfortunately this has also created the side-effect of exact matching keywords (e.g. document names and other exact search phrases) not returning at the top of the search result.

This is despite the fact that many of these search features allow a user to filter results by things like document type and other meta data, which should allow a more specific or targeted results returned.

Has anyone else experienced this during their research and have you found the cause for this? Other research or examples from end users would also be helpful.